Performance of GFR Slope as a Surrogate End Point for Kidney Disease Progression in Clinical Trials: A Statistical Simulation

Add-on astragalus in type 2 diabetes and chronic kidney disease: A multi-center, assessor-blind, randomized controlled trial

BACKGROUND

Diabetes leads to chronic kidney disease (CKD) and kidney failure, requiring dialysis or transplantation. Astragalus, a common herbal medicine and US pharmacopeia-registered food ingredient, is shown kidney protective by retrospective and preclinical data but with limited long-term prospective clinical evidence. This trial aimed to assess the effectiveness of astragalus on kidney function decline in macroalbuminuric diabetic CKD patients.

METHODS

This randomized, assessor-blind, standard care-controlled, multi-center clinical trial randomly assigned 118 patients with estimated glomerular filtration rate (eGFR) of 30-90 ml/min/1.73m2 and urinary albumin-to-creatinine ratio (UACR) of 300-5000 mg/g from 7 public outpatient clinics and the community in Hong Kong between July 2018 and April 2022 to add-on oral astragalus granules (15 gs of raw herbs daily equivalent) or to continue standard care alone as control for 48 weeks. Primary outcomes were the slope of change of eGFR (used for sample size calculation) and UACR of the intention-to-treat population. Secondary outcomes included endpoint blood pressures, biochemistry, biomarkers, concomitant drug change and adverse events. (ClinicalTrials.gov: NCT03535935) RESULTS: During the 48-week period, the estimated difference in the slope of eGFR decline was 4.6 ml/min/1.73m2 per year (95 %CI: 1.5 to 7.6, p = 0.003) slower with astragalus. For UACR, the estimated inter-group proportional difference in the slope of change was insignificant (1.14, 95 %CI: 0.85 to 1.52, p = 0.392). 117 adverse events from 31 astragalus-treated patients and 41 standard care-controlled patients were documented. The 48-week endpoint systolic blood pressure was 7.9 mmHg lower (95 %CI: -12.9 to -2.8, p = 0.003) in the astragalus-treated patients. 113 (96 %) and 107 (91 %) patients had post-randomization and endpoint primary outcome measures, respectively.

CONCLUSION

In patients with type 2 diabetes, stage 2 to 3 CKD and macroalbuminuria, add-on astragalus for 48 weeks further stabilized kidney function on top of standard care.

A meta-analysis of randomized controlled clinical trials implications of acute treatment effects on glomerular filtration rate for long-term kidney protection

Pharmacologic interventions to slow chronic kidney disease progression, such as ACE-inhibitors, angiotensin receptor blockers, or sodium glucose co-transporter 2 inhibitors, often produce acute treatment effects on glomerular filtration rate (GFR) that differ from their long-term chronic treatment effects. Observational studies assessing the implications of acute effects cannot distinguish acute effects from GFR changes unrelated to the treatment. Here, we performed meta-regression analysis of multiple trials to isolate acute effects to determine their long-term implications. In 64 randomized controlled trials (RCTs), enrolling 154,045 participants, we estimated acute effects as the mean between-group difference in GFR slope from baseline to three months, effects on chronic GFR slope (starting at three months after randomization), and effects on three composite kidney endpoints defined by kidney failure (GFR 15 ml/min/1.73m2 or less, chronic dialysis, or kidney transplantation) or sustained GFR declines of 30%, 40% or 57% decline, respectively. We used Bayesian meta-regression to relate acute effects with treatment effects on chronic slope and the composite kidney endpoints. Overall, acute effects were not associated with treatment effects on chronic slope. Acute effects were associated with the treatment effects on composite kidney outcomes such that larger negative acute effects were associated with lesser beneficial effects on the composite kidney endpoints. Associations were stronger when the kidney composite endpoints were defined by smaller thresholds of GFR decline (30% or 40%). Results were similar in a subgroup of interventions with supposedly hemodynamic effects that acutely reduce GFR. For studies with GFR 60 mL/min/1.73m2 or under, negative acute effects were associated with larger beneficial effects on chronic GFR slope. Thus, our data from a large and diverse set of RCTs suggests that acute effects of interventions may influence the treatment effect on clinical kidney outcomes.

Immediate drop of urine osmolality upon tolvaptan initiation predicts impact on renal prognosis in patients with ADPKD

BACKGROUND

Tolvaptan, a vasopressin V2 receptor antagonist, is used for treating autosomal dominant polycystic kidney disease (ADPKD). We focused on changes in urinary osmolality (U-Osm) after tolvaptan initiation to determine whether they were associated with the therapeutic response to tolvaptan.

METHODS

This was a single-centre, prospective, observational cohort study. Seventy-two patients with ADPKD who received tolvaptan were recruited. We analysed the relationship between changes in U-Osm and annual estimated glomerular filtration rate (eGFR) in terms of renal prognostic value using univariable and multivariable linear regression analyses.

RESULTS

The mean value of U-Osm immediately before tolvaptan initiation was 351.8 ± 142.2 mOsm/kg H2O, which decreased to 97.6 ± 23.8 mOsm/kg H2O in the evening. The decrease in U-Osm was maintained in the outpatient clinic 1 month later. However, the 1-month values of U-Osm showed higher variability (160.2 ± 83.8 mOsm/kg H2O) than did those in the first evening of tolvaptan administration. Multivariate analysis revealed that the baseline eGFR, baseline urinary protein and U-Osm change in the evening of the day of admission (initial U-Osm drop) were significantly correlated with the subsequent annual change in eGFR.

CONCLUSIONS

U-Osm can be measured easily and rapidly, and U-Osm change within a short time after tolvaptan initiation may be a useful index for the renal prognosis in actual clinical practice.

Estimated Glomerular Filtration Rate Slope as an Endpoint in Cardiovascular Trials

PURPOSE OF REVIEW

End stage kidney disease can be a slow process and it may be challenging to achieve required follow-up for sufficient events. Therefore, a surrogate kidney endpoint, such as estimated glomerular filtration rate (eGFR) slope maybe attractive to assess the kidney in cardiovascular trials, especially heart failure (HF).

RECENT FINDINGS

eGFR slope can generate informative results in a shorter follow-up period, has decreased risk of type-2 error, and is less sensitive to eGFR shifts compared with other surrogate kidney endpoints (eGFR decline≥40% or doubling creatinine). However, eGFR slope has its limitations with acute effects, heterogeneity in slope calculation/reporting, and deviations from linearity. eGFR slope is a kidney endpoint which may be well-suited for HF trials. Cross-collaborated guideline recommendations are needed to optimize the use of eGFR slope as a kidney endpoint in patients with HF.

Temporal alteration of serum bilirubin levels and its renoprotective effects in diabetic kidney disease: exploring the hormonal mechanisms

Objective

This current study represents a novel endeavor to scrutinize the correlation between the temporal alteration in serum total bilirubin (TBIL) concentrations and the rate of estimated glomerular filtration rate (eGFR). Additionally, this study aims to probe the plausible molecular mechanism underpinning the renoprotective effects of bilirubin concerning its hormonal characteristics.

Materials and methods

In this study, a cohort of 103 patients diagnosed with DKD and receiving medical care at Dongzhimen Hospital were recruited and monitored over a period of 2-7 years. The progression of DKD was ascertained using a threshold of eGFR decline > -5.48%/year. To assess the relationship between the annual change in serum TBIL levels (%/year) and the slope of eGFR, multivariate binary logistic regression analysis was employed. Furthermore, the ROC curve analysis was employed to determine the cut-off value for TBIL levels (%/year).

Results

The use of multivariate binary logistic regression models revealed that serum TBIL levels (%/year) exhibited a significant correlation with the slope of eGFR. Moreover, the ROC curve analysis indicated a cut-off value of -6.729%/year for TBIL levels (%/year) with a sensitivity of 0.75 and specificity of 0.603, in diagnosing eGFR decline >-5.48%/year.

Conclusions

The findings of this study suggest that the sustained elevation of serum bilirubin concentration within the physiological range can effectively retard the progression of Diabetic Kidney Disease (DKD). Furthermore, the hormonal attributes of bilirubin may underlie its renoprotective effects.

Real-world effectiveness of sodium-glucose cotransporter-2 inhibitors on the progression of chronic kidney disease in patients without diabetes, with and without albuminuria

AIM

To examine the renal effects of sodium-glucose cotransporter-2 (SGLT2) inhibition among non-diabetic individuals with chronic kidney disease (CKD) in a real-world setting.

METHODS

We collected de-identified data on adults without diabetes and with an estimated glomerular filtration rate (eGFR) of 25-60 mL/min/1.73 m2, who initiated the SGLT2 inhibitors dapagliflozin or empagliflozin between September 2020 and November 2022 at Maccabi Healthcare Services, an Israeli health maintenance organization. We assessed the effects of SGLT2 inhibitors on renal function (changes in eGFR slope/time). Index date was defined as the date of the first dispensing of SGLT2 inhibitors. Annual baseline slope was calculated using all eGFR measurements during the 2 years prior to index date (median = 7 measurements), while annual follow-up slope was calculated from all evaluations during 90-900 days post index date, along with baseline measurement at index date (median = 6 measurements). Paired t tests were used to compare differences between baseline and follow-up annual slopes.

RESULTS

Of a total of 354 participants with CKD, without diabetes, who received SGLT2 inhibitors and were followed for a median of 527 days, the mean age was 72.8 ± 11.8 years, 26% were female, and 91% used renin-angiotensin system blockade. The mean eGFR was 45.4 ± 9.5 mL/min/1.73 m2. The mean body mass index was 29.1 ± 5.4 kg/m2. During the year before index date, 146 participants (41%) had a urinary albumin to creatinine ratio (UACR) <30 mg/g, 81 (23%) had a UACR of 30-300 mg/g, 74 (21%) had a UACR >300 mg/g, and 53 (15%) had no UACR evaluation. The mean eGFR slope over time was -5.6 ± 7.7 mL/min/1.73 m2 per year at baseline, which improved to -1.7 ± 6.8 mL/min/1.73 m2 per year after SGLT2 inhibitor administration (p <0.001). This effect was independent of UACR.

CONCLUSION

In a real-world study of primarily older non-diabetic adults with CKD, SGLT2 inhibition was associated with a slower rate of kidney function decline, regardless of baseline UACR level.

Are children with IgA nephropathy different from adult patients?

BACKGROUND

Previously, several studies have indicated that pediatric IgA nephropathy (IgAN) might be different from adult IgAN, and treatment strategies might be also different between pediatric IgAN and adult IgAN.

METHODS

We analyzed two prospective cohorts established by pediatric and adult nephrologists, respectively. A comprehensive analysis was performed investigating the difference in clinical and pathological characteristics, treatment, and prognosis between children and adults with IgAN.

RESULTS

A total of 1015 children and 1911 adults with IgAN were eligible for analysis. More frequent gross hematuria (88% vs. 20%, p < 0.0001) and higher proteinuria (1.8 vs. 1.3 g/d, p < 0.0001) were seen in children compared to adults. In comparison, the estimated glomerular filtration rate (eGFR) was lower in adults (80.4 vs. 163 ml/min/1.73 m2, p < 0.0001). Hypertension was more prevalent in adult patients. Pathologically, a higher proportion of M1 was revealed (62% vs. 39%, p < 0.0001) in children than in adults. S1 (62% vs. 28%, p < 0.0001) and T1-2 (34% vs. 8%, p < 0.0001) were more frequent in adults. Adjusted by proteinuria, eGFR, and hypertension, children were more likely to be treated with glucocorticoids than adults (87% vs. 45%, p < 0.0001). After propensity score matching, in IgAN with proteinuria > 1 g/d, children treated with steroids were 1.87 (95% CI 1.16-3.02, p = 0.01) times more likely to reach complete remission of proteinuria compared with adults treated with steroids.

CONCLUSIONS

Children present significantly differently from adults with IgAN in clinical and pathological manifestations and disease progression. Steroid response might be better in children.

Investigating the use of finerenone in children with chronic kidney disease and proteinuria: design of the FIONA and open-label extension studies

INTRODUCTION

Proteinuria is a modifiable risk factor for chronic kidney disease (CKD) progression in children. Finerenone, a selective, non-steroidal, mineralocorticoid receptor antagonist (MRA) has been approved to treat adults with CKD associated with type 2 diabetes mellitus (T2DM) following results from the phase III clinical trials FIDELIO-DKD (NCT02540993) and FIGARO-DKD (NCT02545049). In a pre-specified pooled analysis of both studies (N = 13,026), finerenone was shown to have an acceptable safety profile and was efficacious in decreasing the risk of adverse kidney and cardiovascular outcomes and of proteinuria.

OBJECTIVE

FIONA and the associated open-label extension (OLE) study aim to demonstrate that combining finerenone with an angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) is safe, well-tolerated, and effective in sustainably reducing urinary protein excretion in children with CKD and proteinuria.

DESIGN

FIONA (NCT05196035; Eudra-CT: 2021-002071-19) is a randomized (2:1), double-blind, placebo-controlled, multicenter, phase III study of 6 months' duration in approximately 219 pediatric patients. Patients must have a clinical diagnosis of CKD (an eGFR ≥ 30 mL/min/1.73 m2 if ≥ 1 to < 18 years or a serum creatinine level ≤ 0.40 mg/dL for infants 6 months to < 1 year) with significant proteinuria despite ACEi or ARB usage. The primary objective is to demonstrate that finerenone, added to an ACEi or ARB, is superior to placebo in reducing urinary protein excretion. FIONA OLE (NCT05457283; Eudra-CT: 2021-002905-89) is a single-arm, open-label study, enrolling participants who have completed FIONA. The primary objective of FIONA OLE is to provide long-term safety data. FIONA has two primary endpoints: urinary protein-to-creatinine ratio (UPCR) reduction of ≥ 30% from baseline to day 180 and percent change in UPCR from baseline to day 180. A sample size of 198 participants (aged 2 to < 18 years) in FIONA will provide at least 80% power to reject the null hypothesis of either of the two primary endpoints.

CONCLUSION

FIONA is evaluating the use of finerenone in children with CKD and proteinuria. Should safety, tolerability, and efficacy be demonstrated, finerenone could become a useful additional therapeutic agent in managing proteinuria and improving kidney outcomes in children with CKD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05196035. Registered on 19 January 2022.

Rapid decline of kidney function increases fracture risk in the general population: Insights from TLGS

BACKGROUND

Although the association between Chronic Kidney Disease (CKD) and all-cause fractures was addressed in previous studies, the association between estimated glomerular filtration rate (eGFR) decline and fractures was poorly addressed. For the first time we examined the association between rapid kidney function decline (RKFD) and fracture incidence among Iranian general population.

METHODS

In a Tehranian community-based cohort, RKFD was defined as a 30 % decline in eGFR over 2-3 years. Cox proportional hazards models, adjusted for age, sex, current eGFR, diabetes mellitus, hypertension, dyslipidemia, current smoking, obesity status, waist circumference, prevalent cardiovascular diseases, aspirin, steroid use, education level, and marital status, were used to examine the association of RKFD with different fracture outcomes.

RESULTS

Among 5305 (3031 women) individuals aged ≥30 years, during the median follow-up of 9.62 years, 226 fracture events were observed. The multivariable hazard ratio of RKFD for any-fracture events, lower-extremity, and major osteoporotic fractures were 2.18 (95 % CI, 1.24-3.85), 2.32 (1.15-4.71), and 2.91 (1.29-6.58), respectively. These associations remained significant after accounting for the competing risk of death. The impact of RKFD on the development of incident all-cause fractures was not modified by gender [men: 2.64 (1.11-6.25) vs. women: 2.11 (1.00-4.47)] and according to current CKD status [without CKD: 2.34 (1.00-5.52) vs. with CKD: 2.59 (1.04-6.44)] (all P for interaction >0.5).

CONCLUSIONS

RKFD can increase the incidence of fractures among general population, the issue that was equally important among non-CKD individuals, emphasizing the need for early identification and management in those with rapidly declining eGFR.

TrialView: An AI-powered Visual Analytics System for Temporal Event Data in Clinical Trials

Randomized controlled trials (RCT) are the gold standards for evaluating the efficacy and safety of therapeutic interventions in human subjects. In addition to the pre-specified endpoints, trial participants' experience reveals the time course of the intervention. Few analytical tools exist to summarize and visualize the individual experience of trial participants. Visual analytics allows integrative examination of temporal event patterns of patient experience, thus generating insights for better care decisions. Towards this end, we introduce TrialView, an information system that combines graph artificial intelligence (AI) and visual analytics to enhance the dissemination of trial data. TrialView offers four distinct yet interconnected views: Individual, Cohort, Progression, and Statistics, enabling an interactive exploration of individual and group-level data. The TrialView system is a general-purpose analytical tool for a broad class of clinical trials. The system is powered by graph AI, knowledge-guided clustering, explanatory modeling, and graph-based agglomeration algorithms. We demonstrate the system's effectiveness in analyzing temporal event data through a case study.

Iptacopan in Idiopathic Immune Complex-Mediated Membranoproliferative Glomerulonephritis: Protocol of the APPARENT Multicenter, Randomized Phase 3 Study

Introduction

Immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) is an ultra-rare, fast-progressing kidney disease that may be idiopathic (primary) or secondary to chronic infection, autoimmune disorders, or monoclonal gammopathies. Dysregulation of the alternative complement pathway is implicated in the pathophysiology of IC-MPGN; and currently, there are no approved targeted treatments. Iptacopan is an oral, highly potent proximal complement inhibitor that specifically binds to factor B and inhibits the alternative pathway (AP).

Methods

This randomized, double-blind, placebo-controlled phase 3 study (APPARENT; NCT05755386) will evaluate the efficacy and safety of iptacopan in patients with idiopathic (primary) IC-MPGN, enrolling up to 68 patients (minimum of 10 adolescents) aged 12 to 60 years with biopsy-confirmed IC-MPGN, proteinuria ≥1 g/g, and estimated glomerular filtration rate (eGFR) ≥30 ml/min per 1.73 m2. All patients will receive maximally tolerated angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and vaccination against encapsulated bacteria. Patients with any organ transplant, progressive crescentic glomerulonephritis, or kidney biopsy with >50% interstitial fibrosis/tubular atrophy, will be excluded. Patients will be randomized 1:1 to receive either iptacopan 200 mg twice daily (bid) or placebo for 6 months, followed by open-label treatment with iptacopan 200 mg bid for all patients for 6 months. The primary objective of the study is to evaluate the efficacy of iptacopan versus placebo in proteinuria reduction measured as urine protein-to-creatinine ratio (UPCR) (24-h urine) at 6 months. Key secondary end points will assess kidney function measured by eGFR, patients who achieve a proteinuria-eGFR composite end point, and patient-reported fatigue.

Conclusion

This study will provide evidence toward the efficacy and safety of iptacopan in idiopathic (primary) IC-MPGN.

Interpretation of GFR slope in untreated and treated adult Fabry patients

Nephropathy is one of the main features of Fabry disease (FD) that leads, in untreated patients with classical mutations, to end-stage renal disease (ESRD) from the third to the fifth decade of life. The availability of a specific treatment modified the natural history of FD; in particular, it was widely reported that enzyme replacement therapy (ERT) is able to slow the progression of the disease. Regarding Fabry nephropathy, several reports have documented an elevated estimated glomerular filtration rate (eGFR) slope in untreated patients as expression of a rapid disease progression towards ESRD. Otherwise, the prompt start of treatment may be beneficial in stabilizing renal function or slowing its decline. Therefore, based on data in the literature about the effects of ERT on eGFR decline and on the evidence supporting the role of eGFR slope as a surrogate endpoint for chronic kidney disease progression, we suggest, in this 'Expert Opinion', that a treatment should be defined effective when eGFR decline is <1 ml/min/1.73 m2/year and not effective when eGFR loss remains ≥3 ml/min/1.73 m2/year (≥2.5 ml/min/1.73 m2/year in females). Moreover, practical clinical recommendations and guidance for Fabry patients suggests that a change in treatment may be appropriate if individualized therapeutic goals are not achieved. Since a dose-dependent efficacy has been demonstrated for ERT, we suggest considering a switch to a higher dose of ERT in symptomatic adult Fabry patients (ages 18-60 years) with an eGFR of 45-90 ml/min/1.73 m2 and treated with a stable dose of ERT for at least 1 year, in which a linear negative slope of eGFR of 3 ml/min/1.73 m2/year for males (2.5 ml/min/1.73 m2/year for females) was observed.

Validity and Utility of a Hierarchical Composite End Point for Clinical Trials of Kidney Disease Progression: A Review

Clinical trials in nephrology often use composite end points comprising clinical events, such as onset of ESKD and initiation of kidney function replacement therapy, along with a sustained large ( e.g. , ≥50%) decrease in GFR. Such events typically occur late in the disease course, resulting in large trials in which most participants do not contribute clinical events. In addition, components of the end point are considered of equal importance; however, their clinical significance varies. For example, kidney function replacement therapy initiation is likely to be clinically more meaningful than GFR decline of ≥50%. By contrast, hierarchical composite end points (HCEs) combine multiple outcomes and prioritize each patient's most clinically relevant outcome for inclusion in analysis. In this review, we consider the use of HCEs in clinical trials of CKD progression, emphasizing the potential to combine dichotomous clinical events such as those typically used in CKD progression trials, with the continuous variable of GFR over time, while ranking all components according to clinical significance. We consider maraca plots to visualize overall treatment effects and the contributions of individual components, discuss the application of win odds in kidney HCE trials, and review general design considerations for clinical trials for CKD progression with kidney HCE as an efficacy end point.

Association of eGFR slope with all-cause mortality, macrovascular and microvascular outcomes in people with type 2 diabetes and early-stage chronic kidney disease

AIMS

The association of estimated glomerular filtration rate (eGFR) slope with progression of complications in people with type 2 diabetes (T2D) and early-stage chronic kidney disease (CKD) is less clear.

METHODS

We identified 115,139 T2D participants without decreased eGFR (>60 mL/min/1.73 m2) between 2008 and 2015 from the electronic database of the Hong Kong Hospital Authority. eGFR slope calculated by linear-mixed effects model using 3-year eGFR measurements was categorized into quintiles. With Quintile 3 of eGFR slope as the reference group, we used Cox proportional or cause-specific models to investigate the association between eGFR slope and all-cause mortality, macrovascular and microvascular complications, as appropriate.

RESULTS

Over a median follow-up of 7.8 years, fastest eGFR declines (Quintile 1 with median eGFR slope: -4.32 mL/min/1.73 m2/year) were associated with increased risk of all adverse outcomes (adjusted hazard ratio [aHR] 1.36 to 2.97, all P < 0.0001), compared with less steep eGFR declines (Quintile 3: -1.08 mL/min/1.73 m2/year). Substantial eGFR increases (Quintile 5: 1.34 mL/min/1.73 m2/year) were associated with decreased risk of CKD and ≥ 40 % decline in eGFR (aHR [95 % CI] 0.65 [0.63, 0.67] and 0.85 [0.82, 0.89], respectively) and higher risk of death, CVD, DR and DN (aHR [95 % CI] 1.48 [1.40, 1.56], 1.19 [1.14, 1.25], 1.07 [1.004, 1.15] and 1.62 [1.37, 1.91], respectively).

CONCLUSIONS

In a cohort of T2D people without decreased eGFR, accelerated declines and increases in eGFR were associated with all-cause mortality, macrovascular and microvascular complications, supporting the potential prognostic utility of eGFR slope in T2D people with early-stage CKD.

Effect of Intensive Blood Pressure Control on Kidney Outcomes: Long-Term Electronic Health Record-Based Post-Trial Follow-Up of SPRINT

BACKGROUND

Intensive BP lowering in the Systolic Blood Pressure Intervention Trial (SPRINT) produced acute decreases in kidney function and higher risk for AKI. We evaluated the effect of intensive BP lowering on long-term changes in kidney function using trial and outpatient electronic health record (EHR) creatinine values.

METHODS

SPRINT data were linked with EHR data from 49 (of 102) study sites. The primary outcome was the total slope of decline in eGFR for the intervention phase and the post-trial slope of decline during the observation phase using trial and outpatient EHR values. Secondary outcomes included a ≥30% decline in eGFR to <60 ml/min per 1.73 m 2 and a ≥50% decline in eGFR or kidney failure among participants with baseline eGFR ≥60 and <60 ml/min per 1.73 m 2 , respectively.

RESULTS

EHR creatinine values were available for a median of 8.3 years for 3041 participants. The total slope of decline in eGFR during the intervention phase was -0.67 ml/min per 1.73 m 2 per year (95% confidence interval [CI], -0.79 to -0.56) in the standard treatment group and -0.96 ml/min per 1.73 m 2 per year (95% CI, -1.08 to -0.85) in the intensive treatment group ( P < 0.001). The slopes were not significantly different during the observation phase: -1.02 ml/min per 1.73 m 2 per year (95% CI, -1.24 to -0.81) in the standard group and -0.85 ml/min per 1.73 m 2 per year (95% CI, -1.07 to -0.64) in the intensive group. Among participants without CKD at baseline, intensive treatment was associated with higher risk of a ≥30% decline in eGFR during the intervention (hazard ratio, 3.27; 95% CI, 2.43 to 4.40), but not during the postintervention observation phase. In those with CKD at baseline, intensive treatment was associated with a higher hazard of eGFR decline only during the intervention phase (hazard ratio, 1.95; 95% CI, 1.03 to 3.70).

CONCLUSIONS

Intensive BP lowering was associated with a steeper total slope of decline in eGFR and higher risk for kidney events during the intervention phase of the trial, but not during the postintervention observation phase.

Add-on Rehmannia-6-Based Chinese Medicine in Type 2 Diabetes and CKD: A Multicenter Randomized Controlled Trial

BACKGROUND

Diabetes is the leading cause of CKD and kidney failure. We assessed the real-world effectiveness of Rehmannia-6-based Chinese medicine treatment, the most used Chinese medicine formulation, on the change in eGFR and albuminuria in patients with diabetes and CKD with severely increased albuminuria.

METHODS

In this randomized, assessor-blind, standard care-controlled, parallel, multicenter trial, 148 adult patients from outpatient clinics with type 2 diabetes, an eGFR of 30-90 ml/min per 1.73 m 2 , and a urine albumin-to-creatinine ratio (UACR) of 300-5000 mg/g were randomized 1:1 to a 48-week add-on protocolized Chinese medicine treatment program (using Rehmannia-6-based formulations in the granule form taken orally) or standard care alone. Primary outcomes were the slope of change in eGFR and UACR between baseline and end point (48 weeks after randomization) in the intention-to-treat population. Secondary outcomes included safety and the change in biochemistry, biomarkers, and concomitant drug use.

RESULTS

The mean age, eGFR, and UACR were 65 years, 56.7 ml/min per 1.73 m 2 , and 753 mg/g, respectively. Ninety-five percent ( n =141) of end point primary outcome measures were retrievable. For eGFR, the estimated slope of change was -2.0 (95% confidence interval [CI], -0.1 to -3.9) and -4.7 (95% CI, -2.9 to -6.5) ml/min per 1.73 m 2 in participants treated with add-on Chinese medicine or standard care alone, resulting in a 2.7 ml/min per 1.73 m 2 per year (95% CI, 0.1 to 5.3; P = 0.04) less decline with Chinese medicine. For UACR, the estimated proportion in the slope of change was 0.88 (95% CI, 0.75 to 1.02) and 0.99 (95% CI, 0.85 to 1.14) in participants treated with add-on Chinese medicine or standard care alone, respectively. The intergroup proportional difference (0.89, 11% slower increment in add-on Chinese medicine, 95% CI, 0.72 to 1.10; P = 0.28) did not reach statistical significance. Eighty-five adverse events were recorded from 50 participants (add-on Chinese medicine versus control: 22 [31%] versus 28 [36%]).

CONCLUSIONS

Rehmannia-6-based Chinese medicine treatment stabilized eGFR on top of standard care alone after 48 weeks in patients with type 2 diabetes, stage 2-3 CKD, and severely increased albuminuria.

CLINICAL TRIAL REGISTRY

Semi-individualized Chinese Medicine Treatment as an Adjuvant Management for Diabetic Nephropathy (SCHEMATIC), NCT02488252 .

Long-Term, Real-World Kidney Outcomes with SGLT2i versus DPP4i in Type 2 Diabetes without Cardiovascular or Kidney Disease

BACKGROUND

Contemporary guidelines recommend the use of sodium-glucose cotransporter 2 inhibitors (SGLT2is) independently of glycemic control in patients with type 2 diabetes and those with kidney disease, with heart failure, or at high risk of cardiovascular disease. Using a large Israeli database, we assessed whether long-term use of SGLT2is versus dipeptidyl peptidase 4 inhibitors (DPP4is) is associated with kidney benefits in patients with type 2 diabetes overall and in those without evidence of cardiovascular or kidney disease.

METHODS

Patients with type 2 diabetes who initiated SGLT2is or DPP4is between 2015 and 2021 were propensity score-matched (1:1) according to 90 parameters. The kidney-specific composite outcome included confirmed ≥40% decline in eGFR or kidney failure. The kidney-or-death outcome included also all-cause mortality. Risks of outcomes were assessed using Cox proportional hazard regression models. The between-group difference in eGFR slope was also assessed. Analyses were repeated in patients' subgroup lacking evidence of cardiovascular or kidney disease.

RESULTS

Overall, 19,648 propensity score-matched patients were included; 10,467 (53%) did not have evidence of cardiovascular or kidney disease. Median follow-up was 38 months (interquartile range, 22-55). The composite kidney-specific outcome occurred at an event rate of 6.9 versus 9.5 events per 1000 patient-years with SGLT2i versus DPP4i. The respective event rates of the kidney-or-death outcome were 17.7 versus 22.1. Compared with DPP4is, initiation of SGLT2is was associated with a lower risk for the kidney-specific (hazard ratio [HR], 0.72; 95% confidence interval [CI], 0.61 to 0.86; P < 0.001) and kidney-or-death (HR, 0.80; 95% CI, 0.71 to 0.89; P < 0.001) outcomes. The respective HRs (95% CI) in those lacking evidence of cardiovascular or kidney disease were 0.67 (0.44 to 1.02) and 0.77 (0.61 to 0.97). Initiation of SGLT2is versus DPP4is was associated with mitigation of the eGFR slope overall and in those lacking evidence of cardiovascular or kidney disease (mean between-group differences 0.49 [95% CI, 0.35 to 0.62] and 0.48 [95% CI, 0.32 to 0.64] ml/min per 1.73 m 2 per year, respectively).

CONCLUSIONS

Long-term use of SGLT2is versus DPP4is in a real-world setting was associated with mitigation of eGFR loss in patients with type 2 diabetes, even in those lacking evidence of cardiovascular or kidney disease at baseline.

CKD Progression Prediction in a Diverse US Population: A Machine-Learning Model

Rationale & Objective

Chronic kidney disease (CKD) is a major cause of morbidity and mortality. To date, there are no widely used machine-learning models that can predict progressive CKD across the entire disease spectrum, including the earliest stages. The objective of this study was to use readily available demographic and laboratory data from Sonic Healthcare USA laboratories to train and test the performance of machine learning-based predictive risk models for CKD progression.

Study Design

Retrospective observational study.

Setting & Participants

The study population was composed of deidentified laboratory information services data procured from a large US outpatient laboratory network. The retrospective data set included 110,264 adult patients over a 5-year period with initial estimated glomerular filtration rate (eGFR) values between 15-89 mL/min/1.73 m2.

Predictors

Patient demographic and laboratory characteristics.

Outcomes

Accelerated (ie, >30%) eGFR decline associated with CKD progression within 5 years.

Analytical Approach

Machine-learning models were developed using random forest survival methods, with laboratory-based risk factors analyzed as potential predictors of significant eGFR decline.

Results

The 7-variable risk classifier model accurately predicted an eGFR decline of >30% within 5 years and achieved an area under the curve receiver-operator characteristic of 0.85. The most important predictor of progressive decline in kidney function was the eGFR slope. Other key contributors to the model included initial eGFR, urine albumin-creatinine ratio, serum albumin (initial and slope), age, and sex.

Limitations

The cohort study did not evaluate the role of clinical variables (eg, blood pressure) on the performance of the model.

Conclusions

Our progressive CKD classifier accurately predicts significant eGFR decline in patients with early, mid, and advanced disease using readily obtainable laboratory data. Although prospective studies are warranted, our results support the clinical utility of the model to improve timely recognition and optimal management for patients at risk for CKD progression.

Plain-Language Summary

Defined by a significant decrease in estimated glomerular filtration rate (eGFR), chronic kidney disease (CKD) progression is strongly associated with kidney failure. However, to date, there are no broadly used resources that can predict this clinically significant event. Using machine-learning techniques on a diverse US population, this cohort study aimed to address this deficiency and found that a 5-year risk prediction model for CKD progression was accurate. The most important predictor of progressive decline in kidney function was the eGFR slope, followed by the urine albumin-creatinine ratio and serum albumin slope. Although further study is warranted, the results showed that a machine-learning model using readily obtainable laboratory information accurately predicts CKD progression, which may inform clinical diagnosis and management for this at-risk population.

A meta-analysis of GFR slope as a surrogate endpoint for kidney failure

Glomerular filtration rate (GFR) decline is causally associated with kidney failure and is a candidate surrogate endpoint for clinical trials of chronic kidney disease (CKD) progression. Analyses across a diverse spectrum of interventions and populations is required for acceptance of GFR decline as an endpoint. In an analysis of individual participant data, for each of 66 studies (total of 186,312 participants), we estimated treatment effects on the total GFR slope, computed from baseline to 3 years, and chronic slope, starting at 3 months after randomization, and on the clinical endpoint (doubling of serum creatinine, GFR < 15 ml min-1 per 1.73 m2 or kidney failure with replacement therapy). We used a Bayesian mixed-effects meta-regression model to relate treatment effects on GFR slope with those on the clinical endpoint across all studies and by disease groups (diabetes, glomerular diseases, CKD or cardiovascular diseases). Treatment effects on the clinical endpoint were strongly associated with treatment effects on total slope (median coefficient of determination (R2) = 0.97 (95% Bayesian credible interval (BCI) 0.82-1.00)) and moderately associated with those on chronic slope (R2 = 0.55 (95% BCI 0.25-0.77)). There was no evidence of heterogeneity across disease. Our results support the use of total slope as a primary endpoint for clinical trials of CKD progression.

Effects of newer kidney protective agents on kidney endpoints provide implications for future clinical trials

Doubling of serum creatinine (equivalent to a 57% decline in the estimated glomerular filtration rate (eGFR)) is an accepted component of a composite kidney endpoint in clinical trials. Smaller declines in eGFR (40%, 50%) have been applied in several recently conducted clinical trials. Here, we assessed the effects of newer kidney protective agents on endpoints including smaller proportional declines in eGFR to compare relative event rates and the magnitude of observed treatment effects. We performed a post hoc analysis of 4401 patients in the CREDENCE, 4304 in the DAPA-CKD, 5734 in the FIDELIO-DKD, and 3668 in the SONAR trials, which assessed the effects of canagliflozin, dapagliflozin, finerenone and atrasentan in patients with chronic kidney disease. Effects of active therapies versus placebo on alternative composite kidney endpoints incorporating different eGFR decline thresholds (40%, 50%, or 57% eGFR reductions from baseline) with kidney failure or death due to kidney failure were compared. Cox-proportional hazards regression models were used to assess and compare treatment effects. During follow-up, event rates were higher for endpoints incorporating smaller versus larger eGFR decline thresholds. Compared to the treatment effects on kidney failure or death due to kidney failure, the magnitude of relative treatment effects was generally similar when considering composite endpoints incorporating smaller declines in eGFR. Hazard ratios for the four interventions ranged from 0.63 to 0.82 for the endpoint incorporating 40% eGFR decline and 0.59 to 0.76 for the endpoint incorporating 57% eGFR decline. Clinical trials incorporating a 40% eGFR decline in a composite endpoint would require approximately half the number of participants compared to a 57% eGFR decline with equivalent statistical power. Thus, in populations at high risk of CKD progression, the relative effects of newer kidney protective therapies appear generally similar across endpoints based on varying eGFR decline thresholds.

Glycemic Control and Effects of Canagliflozin in Reducing Albuminuria and eGFR: A Post Hoc Analysis of the CREDENCE Trial

BACKGROUND

In the Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation (CREDENCE) trial, the sodium-glucose cotransporter-2 (SGLT2) inhibitor canagliflozin improved kidney and cardiovascular outcomes and reduced the rate of estimated glomerular filtration decline (eGFR slope) in patients with type 2 diabetes and CKD. In other clinical trials of patients with CKD or heart failure, the protective effects of SGLT2 inhibitors on eGFR slope were greater in participants with versus participants without type 2 diabetes. This post hoc analysis of the CREDENCE trial assessed whether the effects of canagliflozin on eGFR slope varied according to patient subgroups by baseline glycated hemoglobin A1c (HbA1c).

METHODS

CREDENCE ( ClinicalTrials.gov [ NCT02065791 ]) was a randomized controlled trial in adults with type 2 diabetes with an HbA1c of 6.5%-12.0%, an eGFR of 30-90 ml/min per 1.73 m 2 , and a urinary albumin-to-creatinine ratio of 300-5000 mg/g. Participants were randomly assigned to canagliflozin 100 mg once daily or placebo. We studied the effect of canagliflozin on eGFR slope using linear mixed-effects models.

RESULTS

The annual difference in total eGFR slope was 1.52 ml/min per 1.73 m 2 (95% confidence interval [CI], 1.11 to 1.93) slower in participants randomized to canagliflozin compared with placebo. The rate of eGFR decline was faster in those with poorer baseline glycemic control. The mean difference in total eGFR slope between canagliflozin and placebo was greater in participants with poorer baseline glycemic control (difference in eGFR slope of 0.39, 1.36, 2.60, 1.63 ml/min per 1.73 m 2 for HbA1c subgroups 6.5%-7.0%, 7.0%-8.0%, 8.0%-10.0%, 10.0%-12.0%, respectively; Pinteraction = 0.010). The mean difference in change from baseline in urinary albumin-to-creatinine ratio between participants randomized to canagliflozin and placebo was smaller in patients with baseline HbA1c 6.5%-7.0% (-17% [95% CI, -28 to -5]) compared with those with an HbA1c of 7.0%-12% (-32% [95% CI, -40 to -28]; Pinteraction = 0.03).

CONCLUSIONS

The effect of canagliflozin on eGFR slope in patients with type 2 diabetes and CKD was more pronounced in patients with higher baseline HbA1c, partly because of the more rapid decline in kidney function in these individuals.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Evaluation of the Effects of Canagliflozin on Renal and Cardiovascular Outcomes in Participants With Diabetic Nephropathy (CREDENCE), NCT02065791.

Efficacy of Empagliflozin in Patients With Heart Failure Across Kidney Risk Categories

BACKGROUND

Empagliflozin reduces the risk of major heart failure outcomes in heart failure with reduced or preserved ejection fraction.

OBJECTIVES

The goal of this study was to evaluate the effect of empagliflozin across the spectrum of chronic kidney disease in a pooled analysis of EMPEROR-Reduced and EMPEROR-Preserved (Empagliflozin Outcome Trial in Patients with Chronic Heart Failure with Reduced or Preserved Ejection Fraction, respectively).

METHODS

A total of 9,718 patients were grouped into Kidney Disease Improving Global Outcomes (KDIGO) categories based on estimated glomerular filtration rate (eGFR) and urine albumin-to-creatinine ratio into low-, moderate-, high-, and very-high-risk categories, comprising 32.0%, 29.1%, 21.9%, and 17.0% of the participants, respectively.

RESULTS

In the placebo arm, when compared with lower risk categories, patients at higher risk experienced a slower rate of decline in eGFR, but a higher risk of a composite kidney event. Empagliflozin reduced the risk of cardiovascular death or heart failure hospitalizations similarly in all KDIGO categories (HR: 0.81; 95% CI: 0.66-1.01 for low-; HR: 0.63; 95% CI: 0.52-0.76 for moderate-; HR: 0.82; 95% CI: 0.68-0.98 for high-; and HR: 0.84; 95% CI: 0.71-1.01 for very-high-risk groups; P trend = 0.30). Empagliflozin reduced the rate of decline in eGFR whether it was estimated by chronic slope, total slope, or unconfounded slope. When compared with the unconfounded slope, the magnitude of the effect on chronic slope was larger, and the effect on total slope was smaller. In EMPEROR-Reduced, patients at lowest risk experienced the largest effect of empagliflozin on eGFR slope; this pattern was not observed in EMPEROR-Preserved.

CONCLUSIONS

The benefit of empagliflozin on major heart failure events was not influenced by KDIGO categories. The magnitude of the renal effects of the drug depended on the approach used to calculate eGFR slopes.

Novel Genetic Variants Associated with Chronic Kidney Disease Progression

SIGNIFICANCE STATEMENT

eGFR slope has been used as a surrogate outcome for progression of CKD. However, genetic markers associated with eGFR slope among patients with CKD were unknown. We aimed to identify genetic susceptibility loci associated with eGFR slope. A two-phase genome-wide association study identified single nucleotide polymorphisms (SNPs) in TPPP and FAT1-LINC02374 , and 22 of them were used to derive polygenic risk scores that mark the decline of eGFR by disrupting binding of nearby transcription factors. This work is the first to identify the impact of TPPP and FAT1-LINC02374 on CKD progression, providing predictive markers for the decline of eGFR in patients with CKD.

BACKGROUND

The incidence of CKD is associated with genetic factors. However, genetic markers associated with the progression of CKD have not been fully elucidated.

METHODS

We conducted a genome-wide association study among 1738 patients with CKD, mainly from the KoreaN cohort study for Outcomes in patients With CKD. The outcome was eGFR slope. We performed a replication study for discovered single nucleotide polymorphisms (SNPs) with P <10 -6 in 2498 patients with CKD from the Chronic Renal Insufficiency Cohort study. Several expression quantitative trait loci (eQTL) studies, pathway enrichment analyses, exploration of epigenetic architecture, and predicting disruption of transcription factor (TF) binding sites explored potential biological implications of the loci. We developed and evaluated the effect of polygenic risk scores (PRS) on incident CKD outcomes.

RESULTS

SNPs in two novel loci, TPPP and FAT1-LINC02374 , were replicated (rs59402340 in TPPP , Pdiscovery =7.11×10 -7 , PCRIC =8.13×10 -4 , Pmeta =7.23×10 -8 ; rs28629773 in FAT1-LINC02374 , Pdiscovery =6.08×10 -7 , PCRIC =4.33×10 -2 , Pmeta =1.87×10 -7 ). The eQTL studies revealed that the replicated SNPs regulated the expression level of nearby genes associated with kidney function. Furthermore, these SNPs were near gene enhancer regions and predicted to disrupt the binding of TFs. PRS based on the independently significant top 22 SNPs were significantly associated with CKD outcomes.

CONCLUSIONS

This study demonstrates that SNP markers in the TPPP and FAT1-LINC02374 loci could be predictive markers for the decline of eGFR in patients with CKD.

Clinical prediction model for prognosis in kidney transplant recipients (KIDMO): study protocol

BACKGROUND

Many potential prognostic factors for predicting kidney transplantation outcomes have been identified. However, in Switzerland, no widely accepted prognostic model or risk score for transplantation outcomes is being routinely used in clinical practice yet. We aim to develop three prediction models for the prognosis of graft survival, quality of life, and graft function following transplantation in Switzerland.

METHODS

The clinical kidney prediction models (KIDMO) are developed with data from a national multi-center cohort study (Swiss Transplant Cohort Study; STCS) and the Swiss Organ Allocation System (SOAS). The primary outcome is the kidney graft survival (with death of recipient as competing risk); the secondary outcomes are the quality of life (patient-reported health status) at 12 months and estimated glomerular filtration rate (eGFR) slope. Organ donor, transplantation, and recipient-related clinical information will be used as predictors at the time of organ allocation. We will use a Fine & Gray subdistribution model and linear mixed-effects models for the primary and the two secondary outcomes, respectively. Model optimism, calibration, discrimination, and heterogeneity between transplant centres will be assessed using bootstrapping, internal-external cross-validation, and methods from meta-analysis.

DISCUSSION

Thorough evaluation of the existing risk scores for the kidney graft survival or patient-reported outcomes has been lacking in the Swiss transplant setting. In order to be useful in clinical practice, a prognostic score needs to be valid, reliable, clinically relevant, and preferably integrated into the decision-making process to improve long-term patient outcomes and support informed decisions for clinicians and their patients. The state-of-the-art methodology by taking into account competing risks and variable selection using expert knowledge is applied to data from a nationwide prospective multi-center cohort study. Ideally, healthcare providers together with patients can predetermine the risk they are willing to accept from a deceased-donor kidney, with graft survival, quality of life, and graft function estimates available for their consideration.

STUDY REGISTRATION

Open Science Framework ID: z6mvj.

Changes in urinary albumin as a surrogate for kidney disease progression in people with type 2 diabetes

BACKGROUND

It remains unclear whether urinary albumin changes can predict subsequent kidney disease progression in people with diabetes.

METHODS

This retrospective cohort study included 4570 Japanese adults with type 2 diabetes (T2D). The exposure was changes in urinary albumin-to-creatinine ratio (UACR) over 3 years, categorized into three categories: ≤ - 30%, minor change, or ≥ 30%. During the exposure period, eGFR decline was also examined and categorized into two categories: < 30% or ≥ 30% decline. The primary outcome was the composite of eGFR halving or initiation of kidney replacement therapy (KRT). The secondary outcome was the initiation of KRT.

RESULTS

In the spline model, the hazard ratio for the primary outcome increased linearly on the log₂ scale of UACR changes. When classified into six groups based on the categories of UACR changes and eGFR decline, people with a ≤ - 30% UACR change and < 30% eGFR decline had a 38% lower incidence of the outcome compared to those with a minor UACR change and < 30% eGFR decline. Meanwhile, the risk in those with a ≤ - 30% UACR change and ≥ 30% eGFR decline was 2.89 times. People with a ≥ 30% UACR change had the higher risk, regardless of whether a ≥ 30% eGFR decline occurred. Similar results were obtained in the secondary outcome.

CONCLUSIONS

UACR changes can be a useful surrogate for kidney disease progression in people with T2D. However, when setting a decrease in UACR as the surrogate, it may be necessary to simultaneously evaluate kidney function decline.

The Effect of Metabolic Syndrome and Its Individual Components on Renal Function: A Meta-Analysis

BACKGROUND

Observational studies have reported inconsistent findings in the relationship between metabolic syndrome (MetS), its components, and loss of renal function, mainly including eGFR decline, new-onset CKD, and ESRD. This meta-analysis was performed to investigate their potential associations.

METHODS

PubMed and EMBASE were systematically searched from their inception to 21 July 2022. Observational cohort studies in English assessing the risk of renal dysfunction in individuals with MetS were identified. Risk estimates and their 95% confidence intervals (CIs) were extracted and pooled using the random-effects approach.

RESULTS

A total of 32 studies with 413,621 participants were included in the meta-analysis. MetS contributed to higher risks of renal dysfunction (RR = 1.50, 95% CI = 1.39-1.61) and, specifically, rapid decline in eGFR (RR 1.31, 95% CI 1.13-1.51), new-onset CKD (RR 1.47, 95% CI 1.37-1.58), as well as ESRD (RR 1.55, 95% CI 1.08-2.22). Moreover, all individual components of MetS were significantly associated with renal dysfunction, while elevated BP conveyed the highest risk (RR = 1.37, 95% CI = 1.29-1.46), impaired fasting glucose with the lowest and diabetic-dependent risk (RR = 1.20, 95% CI = 1.09-1.33).

CONCLUSIONS

Individuals with MetS and its components are at higher risk of renal dysfunction.

Evaluation of Variation in the Performance of GFR Slope as a Surrogate End Point for Kidney Failure in Clinical Trials that Differ by Severity of CKD

BACKGROUND

The GFR slope has been evaluated as a surrogate end point for kidney failure in meta-analyses on a broad collection of randomized controlled trials (RCTs) in CKD. These analyses evaluate how accurately a treatment effect on GFR slope predicts a treatment effect on kidney failure. We sought to determine whether severity of CKD in the patient population modifies the performance of GFR slope.

METHODS

We performed Bayesian meta-regression analyses on 66 CKD RCTs to evaluate associations between effects on GFR slope (the chronic slope and the total slope over 3 years, expressed as mean differences in ml/min per 1.73 m2/yr) and those of the clinical end point (doubling of serum creatinine, GFR <15 ml/min per 1.73 m2, or kidney failure, expressed as a log-hazard ratio), where models allow interaction with variables defining disease severity. We evaluated three measures (baseline GFR in 10 ml/min per 1.73 m2, baseline urine albumin-to-creatinine ratio [UACR] per doubling in mg/g, and CKD progression rate defined as the control arm chronic slope, in ml/min per 1.73 m2/yr) and defined strong evidence for modification when 95% posterior credible intervals for interaction terms excluded zero.

RESULTS

There was no evidence for modification by disease severity when evaluating 3-year total slope (95% credible intervals for the interaction slope: baseline GFR [-0.05 to 0.03]; baseline UACR [-0.02 to 0.04]; CKD progression rate [-0.07 to 0.02]). There was strong evidence for modification in evaluations of chronic slope (95% credible intervals: baseline GFR [0.02 to 0.11]; baseline UACR [-0.11 to -0.02]; CKD progression rate [0.01 to 0.15]).

CONCLUSIONS

These analyses indicate consistency of the performance of total slope over 3 years, which provides further evidence for its validity as a surrogate end point in RCTs representing varied CKD populations.

Dapagliflozin and Kidney Outcomes in Patients With Heart Failure With Mildly Reduced or Preserved Ejection Fraction: A Prespecified Analysis of the DELIVER Randomized Clinical Trial

Importance

Sodium-glucose cotransporter 2 inhibitors are known to reduce heart failure events and slow progression of kidney disease among patients with heart failure and a reduced ejection fraction.

Objective

To determine the effect of dapagliflozin on cardiovascular and kidney outcomes and the influence of baseline kidney disease among patients with heart failure and a mildly reduced or preserved ejection fraction enrolled in the Dapagliflozin Evaluation to Improve the Lives of Patients With Preserved Ejection Fraction Heart Failure (DELIVER) trial.

Design, Setting, and Participants

This was a prespecified analysis conducted from July 1 to September 18, 2022 of the DELIVER randomized clinical trial. This was an international, multicenter trial including patients with ejection fraction greater than 40% and estimated glomerular filtration rate (eGFR) of 25 mL/min/1.73 m2 or higher.

Interventions

Dapagliflozin, 10 mg, per day or placebo.

Main Outcomes and Measures

Outcomes assessed were whether baseline kidney function modified the treatment effect on the primary outcome (cardiovascular death or worsening heart failure). Also examined was the treatment effect on the prespecified outcomes of eGFR slope and a post hoc composite kidney outcome (first ≥50% decline in eGFR from baseline; first eGFR <15 mL/min/1.73 m2; end-stage kidney disease; death from kidney causes).

Results

A total of 6262 patients (mean [SD] age, 72 [10] years; 3516 male [56%]) had mean (SD) eGFR measurements available: 61 (19) mL/min/1.73 m2; 3070 patients (49%) had an eGFR less than 60 mL/min/1.73 m2. The effect of dapagliflozin on the primary outcome was not influenced by baseline eGFR category (eGFR ≥60 mL/min/1.73 m2: hazard ratio [HR], 0.84; 95% CI, 0.70-1.00; eGFR 45-<60 mL/min/1.73 m2: HR, 0.68; 95% CI, 0.54-0.87; eGFR <45 mL/min/1.73 m2: HR, 0.93; 95% CI, 0.76-1.14; P for interaction = .16). Over a median (IQR) follow-up of 2.3 (1.7-2.8) years, the overall incidence rate of the kidney composite outcome was low (1.1 events per 100 patient-years) and was not affected by treatment with dapagliflozin (HR, 1.08; 95% CI, 0.79-1.49). However, dapagliflozin attenuated the decline in eGFR from baseline (difference, 0.5; 95% CI, 0.1-0.9 mL/min/1.73 m2 per year; P = .01) and from month 1 to 36 (difference, 1.4; 95% CI, 1.0-1.8) mL/min/1.73 m2 per year; P < .001).

Conclusions and Relevance

Results of this prespecified analysis showed that baseline kidney function did not modify the benefit of dapagliflozin in patients with heart failure and a mildly reduced or preserved ejection fraction. Dapagliflozin did not significantly reduce the frequency of the kidney composite outcome, although the overall event rate was low. However, dapagliflozin slowed the rate of decline in eGFR compared with placebo.

Trial Registration

ClinicalTrials.gov Identifier: NCT03619213.

Development and Validation of a Lifetime Risk Model for Kidney Failure and Treatment Benefit in Type 2 Diabetes: 10-Year and Lifetime Risk Prediction Models

BACKGROUND AND OBJECTIVES

Individuals with type 2 diabetes are at a higher risk of developing kidney failure. The objective of this study was to develop and validate a decision support tool for estimating 10-year and lifetime risks of kidney failure in individuals with type 2 diabetes as well as estimating individual treatment effects of preventive medication.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The prediction algorithm was developed in 707,077 individuals with prevalent and incident type 2 diabetes from the Swedish National Diabetes Register for 2002-2019. Two Cox proportional regression functions for kidney failure (first occurrence of kidney transplantation, long-term dialysis, or persistent eGFR <15 ml/min per 1.73 m2) and all-cause mortality as respective end points were developed using routinely available predictors. These functions were combined into life tables to calculate the predicted survival without kidney failure while using all-cause mortality as the competing outcome. The model was externally validated in 256,265 individuals with incident type 2 diabetes from the Scottish Care Information Diabetes database between 2004 and 2019.

RESULTS

During a median follow-up of 6.8 years (interquartile range, 3.2-10.6), 8004 (1%) individuals with type 2 diabetes in the Swedish National Diabetes Register cohort developed kidney failure, and 202,078 (29%) died. The model performed well, with c statistics for kidney failure of 0.89 (95% confidence interval, 0.88 to 0.90) for internal validation and 0.74 (95% confidence interval, 0.73 to 0.76) for external validation. Calibration plots showed good agreement in observed versus predicted 10-year risk of kidney failure for both internal and external validation.

CONCLUSIONS

This study derived and externally validated a prediction tool for estimating 10-year and lifetime risks of kidney failure as well as life years free of kidney failure gained with preventive treatment in individuals with type 2 diabetes using easily available clinical predictors.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2022_11_04_CJN05020422.mp3.

Glycated Haemoglobin A1c Variability Score Elicits Kidney Function Decline in Chinese People Living with Type 2 Diabetes

Our aim was to investigate the association of glycated haemoglobin A1c (HbA1c) variability score (HVS) with estimated glomerular filtration rate (eGFR) slope in Chinese adults living with type 2 diabetes. This cohort study included adults with type 2 diabetes attending outpatient clinics between 2011 and 2019 from a large electronic medical record-based database of diabetes in China (WECODe). We estimated the individual-level visit-to-visit HbA1c variability using HVS, a proportion of changes in HbA1c of ≥0.5% (5.5 mmol/mol). We estimated the odds of people experiencing a rapid eGFR annual decline using a logistic regression and differences across HVS categories in the mean eGFR slope using a mixed-effect model. The analysis involved 2397 individuals and a median follow-up of 4.7 years. Compared with people with HVS ≤ 20%, those with HVS of 60% to 80% had 11% higher odds of experiencing rapid eGFR annual decline, with an extra eGFR decline of 0.93 mL/min/1.73 m2 per year on average; those with HVS > 80% showed 26% higher odds of experiencing a rapid eGFR annual decline, with an extra decline of 1.83 mL/min/1.73 m2 per year on average. Chinese adults with type 2 diabetes and HVS > 60% could experience a more rapid eGFR decline.

Selecting the right therapeutic target for kidney disease

Kidney disease is a complex disease with several different etiologies and underlying associated pathophysiology. This is reflected by the lack of effective treatment therapies in chronic kidney disease (CKD) that stop disease progression. However, novel strategies, recent scientific breakthroughs, and technological advances have revealed new possibilities for finding novel disease drivers in CKD. This review describes some of the latest advances in the field and brings them together in a more holistic framework as applied to identification and validation of disease drivers in CKD. It uses high-resolution ‘patient-centric’ omics data sets, advanced in silico tools (systems biology, connectivity mapping, and machine learning) and ‘state-of-the-art‘ experimental systems (complex 3D systems in vitro, CRISPR gene editing, and various model biological systems in vivo). Application of such a framework is expected to increase the likelihood of successful identification of novel drug candidates based on strong human target validation and a better scientific understanding of underlying mechanisms.

Clinical Trial Considerations in Developing Treatments for Early Stages of Common, Chronic Kidney Diseases: A Scientific Workshop Cosponsored by the National Kidney Foundation and the US Food and Drug Administration

In the past decade, advances in the validation of surrogate end points for chronic kidney disease (CKD) progression have heightened interest in evaluating therapies in early CKD. In December 2020, the National Kidney Foundation sponsored a scientific workshop in collaboration with the US Food and Drug Administration (FDA) to explore patient, provider, and payor perceptions of the value of treating early CKD. The workshop reviewed challenges for trials in early CKD, including trial designs, identification of high-risk populations, and cost-benefit and safety considerations. Over 90 people representing a range of stakeholders including experts in clinical trials, nephrology, cardiology and endocrinology, patient advocacy organizations, patients, payors, health economists, regulators and policy makers attended a virtual meeting. There was consensus among the attendees that there is value to preventing the development and treating the progression of early CKD in people who are at high risk for progression, and that surrogate end points should be used to establish efficacy. Attendees also concluded that cost analyses should be holistic and include aspects beyond direct savings for treatment of kidney failure; and that safety data should be collected outside/beyond the duration of a clinical trial. Successful drug development and implementation of effective therapies will require collaboration across sponsors, patients, patient advocacy organizations, medical community, regulators, and payors.

Review of potential biomarkers of inflammation and kidney injury in diabetic kidney disease

Diabetic kidney disease is expected to increase rapidly over the coming decades with rising prevalence of diabetes worldwide. Current measures of kidney function based on albuminuria and estimated glomerular filtration rate do not accurately stratify and predict individuals at risk of declining kidney function in diabetes. As a result, recent attention has turned towards identifying and assessing the utility of biomarkers in diabetic kidney disease. This review explores the current literature on biomarkers of inflammation and kidney injury focussing on studies of single or multiple biomarkers between January 2014 and February 2020. Multiple serum and urine biomarkers of inflammation and kidney injury have demonstrated significant association with the development and progression of diabetic kidney disease. Of the inflammatory biomarkers, tumour necrosis factor receptor-1 and -2 were frequently studied and appear to hold most promise as markers of diabetic kidney disease. With regards to kidney injury biomarkers, studies have largely targeted markers of tubular injury of which kidney injury molecule-1, beta-2-microglobulin and neutrophil gelatinase-associated lipocalin emerged as potential candidates. Finally, the use of a small panel of selective biomarkers appears to perform just as well as a panel of multiple biomarkers for predicting kidney function decline.

Angiotensin-neprilysin inhibition and renal outcomes across the spectrum of ejection fraction in heart failure

AIMS

Patients with heart failure are at higher risk of progression to end-stage renal disease (ESRD), regardless of ejection fraction (EF). We assessed the renal effects of angiotensin-neprilysin inhibition in a pooled analysis of 13 195 patients with heart failure with reduced and preserved EF.

METHODS AND RESULTS

We combined data from PARADIGM-HF (EF ≤40%; n = 8399) and PARAGON-HF (EF ≥45%; n = 4796) in a pre-specified pooled analysis. We assessed the effect of treatment (sacubitril/valsartan vs. enalapril or valsartan) on a composite of either ≥50% reduction in estimated glomerular filtration rate (eGFR), ESRD, or death from renal causes, in addition to changes in eGFR slope. We assessed whether baseline renal function or EF modified the effect of therapy on renal outcomes. At randomization, eGFR was 68 ± 20 ml/min/1.73 m2 in PARADIGM-HF and 63 ± 19 ml/min/1.73 m2 in PARAGON-HF. The composite renal outcome occurred in 70 of 6594 patients (1.1%) in the sacubitril/valsartan group and in 123 of 6601 patients (1.9%) in the valsartan or enalapril group (hazard ratio 0.56, 95% confidence interval [CI] 0.42-0.75; p < 0.001). The mean eGFR change was -1.8 (95% CI -1.9 to -1.7) ml/min/1.73 m2 /year for the sacubitril/valsartan group, compared with -2.4 (95% CI -2.5 to -2.2) ml/min/1.73 m2 /year for the valsartan or enalapril group. The treatment effect on the composite renal endpoint was not modified by categories of baseline eGFR (p-interaction = 0.64), but was most pronounced in those with baseline EF between 30% and 60% (p-interaction = 0.001).

CONCLUSIONS

In patients with heart failure, sacubitril/valsartan reduced the risk of serious adverse renal outcomes and slowed decline in eGFR, compared with valsartan or enalapril, independent of baseline renal function.

Using CUSUM in real time to signal clinically relevant decreases in estimated glomerular filtration rate

Background

The electronic health record (EHR), utilized to apply statistical methodology, assists provider decision-making, including during the care of chronic kidney disease (CKD) patients. When estimated glomerular filtration (eGFR) decreases, the rate of that change adds meaning to a patient’s single eGFR and may represent severity of renal injury. Since the cumulative sum chart technique (CUSUM), often used in quality control and surveillance, continuously checks for change in a series of measurements, we selected this statistical tool to detect clinically relevant eGFR decreases and developed CUSUM_GFR.

Methods

In a retrospective analysis we applied an age adjusted CUSUM_GFR, to signal identification of eventual ESKD patients prior to diagnosis date. When the patient signaled by reaching a specified threshold value, days from CUSUM signal date to ESKD diagnosis date (earliness days) were measured, along with the corresponding eGFR measurement at the signal.

Results

Signaling occurred by CUSUM_GFR on average 791 days (se = 12 days) prior to ESKD diagnosis date with sensitivity = 0.897, specificity = 0.877, and accuracy = .878. Mean days prior to ESKD diagnosis were significantly greater in Black patients (905 days) and patients with hypertension (852 days), diabetes (940 days), cardiovascular disease (1027 days), and hypercholesterolemia (971 days). Sensitivity and specificity did not vary by sociodemographic and clinical risk factors.

Conclusions

CUSUM_GFR correctly identified 30.6% of CKD patients destined for ESKD when eGFR was > 60 ml/min/1.73 m² and signaled 12.3% of patients that did not go on to ESKD (though almost all went on to later-stage CKD). If utilized in an EHR, signaling patients could focus providers’ efforts to slow or prevent progression to later stage CKD and ESKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02910-8.

Alternative Complement Pathway Inhibition With Iptacopan for the Treatment of C3 Glomerulopathy-Study Design of the APPEAR-C3G Trial

Introduction

Complement 3 glomerulopathy (C3G) is a rare kidney disease characterized by dysregulation of the alternative pathway (AP) of the complement system. About 50% of patients with C3G progress to kidney failure within 10 years of diagnosis. Currently, there are no approved therapeutic agents for C3G. Iptacopan is an oral, first-in-class, potent, and selective inhibitor of factor B, a key component of the AP. In a Phase II study, treatment with iptacopan was associated with a reduction in proteinuria and C3 deposit scores in C3G patients with native and transplanted kidneys, respectively.

Methods

APPEAR-C3G (NCT04817618) is a randomized, double-blind, and placebo-controlled Phase III study to evaluate the efficacy and safety of iptacopan in C3G patients, enrolling 68 adults with biopsy-confirmed C3G, reduced C3 (<77 mg/dl), proteinuria ≥1.0 g/g, and estimated glomerular filtration rate (eGFR) ≥30 ml/min per 1.73 m². All patients will receive maximally tolerated angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and vaccination against encapsulated bacteria. Patients with any organ transplantation, progressive crescentic glomerulonephritis (GN), monoclonal gammopathy of undetermined significance, or kidney biopsy with >50% interstitial fibrosis/tubular atrophy, will be excluded. Patients will be randomized 1:1 to receive either iptacopan 200 mg twice daily or placebo for 6 months, followed by open-label treatment with iptacopan 200 mg twice daily for all patients for 6 months. The primary objective is to evaluate the efficacy of iptacopan versus placebo on proteinuria reduction urine protein:creatinine ratio (UPCR) (24 h urine). Key secondary endpoints will assess kidney function measured by eGFR, histological disease total activity score, and fatigue.

Conclusion

This study aims to demonstrate the clinical benefits of AP inhibition with iptacopan in C3G.

Allograft Function as Endpoint for Clinical Trials in Kidney Transplantation

Clinical study endpoints that assess the efficacy of interventions in patients with chronic renal insufficiency can be adopted for use in kidney transplantation trials, given the pathophysiological similarities between both conditions. Kidney dysfunction is reflected in the glomerular filtration rate (GFR), and although a predefined (e.g., 50%) reduction in GFR was recommended as an endpoint by the European Medicines Agency (EMA) in 2016, many other endpoints are also included in clinical trials. End-stage renal disease is strongly associated with a change in estimated (e)GFR, and eGFR trajectories or slopes are increasingly used as endpoints in clinical intervention trials in chronic kidney disease (CKD). Similar approaches could be considered for clinical trials in kidney transplantation, although several factors should be taken into account. The present Consensus Report was developed from documentation produced by the European Society for Organ Transplantation (ESOT) as part of a Broad Scientific Advice request that ESOT submitted to the EMA in 2020. This paper provides a contemporary discussion of primary endpoints used in clinical trials involving CKD, including proteinuria and albuminuria, and evaluates the validity of these concepts as endpoints for clinical trials in kidney transplantation.

Glomerular filtration rate as a kidney outcome of diabetic kidney disease: a focus on new antidiabetic drugs

Diabetes has reached epidemic proportions, both in Korea and worldwide and is associated with an increased risk of chronic kidney disease and kidney failure (KF). The natural course of kidney function among people with diabetes (especially type 2 diabetes) may be complex in real-world situations. Strong evidence from observational data and clinical trials has demonstrated a consistent association between decreased estimated glomerular filtration rate (eGFR) and subsequent development of hard renal endpoints (such as KF or renal death). The disadvantage of hard renal endpoints is that they require a long follow-up duration. In addition, there are many patients with diabetes whose renal function declines without the appearance of albuminuria, measurement of the eGFR is emphasized. Many studies have used GFR-related parameters, such as its change, decline, or slope, as clinical endpoints for kidney disease progression. In this respect, understanding the trends in GFR changes could be crucial for developing clinical management strategies for the prevention of diabetic complications. This review focuses on the clinical implication of the eGFR-related parameters that have been used so far in diabetic kidney disease. We also discuss the use of recently developed new antidiabetic drugs for kidney protection, with a focus on the GFR as clinical endpoints.

Initial decline in eGFR to predict tolvaptan response in autosomal-dominant polycystic kidney disease

BACKGROUND

Tolvaptan, a vasopressin V2 receptor antagonist, is used to treat autosomal-dominant polycystic kidney disease (ADPKD). Although tolvaptan curbs disease progression, a few reports have examined factors related to treatment response. The estimated glomerular filtration rate (eGFR) decreases soon after tolvaptan is initiated. We investigated whether initial eGFR decline affects renal prognosis of patients.

METHODS

This was a single-center, retrospective observational cohort study. Eighty-three patients with ADPKD who initiated tolvaptan were selected. We analyzed the relationship of the initial eGFR change with clinical parameters and analyzed the annual eGFR change in terms of renal prognostic value using univariable and multivariable linear regression analyses.

RESULTS

The initial eGFR change was - 4.6 ± 8.0%/month. The initial eGFR change correlated significantly with the annual eGFR change in multivariable analysis, suggesting that the larger decline in the initial eGFR change, the better the renal prognosis. Furthermore, the change in fractional excretion (FE) of free water (FEH₂O) correlated positively with initial eGFR change. FEH₂O and urea nitrogen FE (FEUN) increased significantly; however, sodium FE (FENa) level remained unchanged. In approximately half of the patients, FENa unexpectedly decreased.

CONCLUSIONS

The initial eGFR decline might be caused by suppressing glomerular hyperfiltration, due to the pharmacological effect of tolvaptan, and/or by reducing renal plasma flow, due to potential volume depletion. The initial eGFR change reflects the tolvaptan effect, can be easily evaluated in clinical practice, and may be useful as one of the clinical indicator for predicting renal prognosis in patients under tolvaptan.

The applications of DNA methylation as a biomarker in kidney transplantation: a systematic review

Background

Although kidney transplantation improves patient survival and quality of life, long-term results are hampered by both immune- and non-immune-mediated complications. Current biomarkers of post-transplant complications, such as allograft rejection, chronic renal allograft dysfunction, and cutaneous squamous cell carcinoma, have a suboptimal predictive value. DNA methylation is an epigenetic modification that directly affects gene expression and plays an important role in processes such as ischemia/reperfusion injury, fibrosis, and alloreactive immune response. Novel techniques can quickly assess the DNA methylation status of multiple loci in different cell types, allowing a deep and interesting study of cells’ activity and function. Therefore, DNA methylation has the potential to become an important biomarker for prediction and monitoring in kidney transplantation.

Purpose of the study

The aim of this study was to evaluate the role of DNA methylation as a potential biomarker of graft survival and complications development in kidney transplantation.

Material and Methods

A systematic review of several databases has been conducted. The Newcastle–Ottawa scale and the Jadad scale have been used to assess the risk of bias for observational and randomized studies, respectively.

Results

Twenty articles reporting on DNA methylation as a biomarker for kidney transplantation were included, all using DNA methylation for prediction and monitoring. DNA methylation pattern alterations in cells isolated from different tissues, such as kidney biopsies, urine, and blood, have been associated with ischemia–reperfusion injury and chronic renal allograft dysfunction. These alterations occurred in different and specific loci. DNA methylation status has also proved to be important for immune response modulation, having a crucial role in regulatory T cell definition and activity. Research also focused on a better understanding of the role of this epigenetic modification assessment for regulatory T cells isolation and expansion for future tolerance induction-oriented therapies.

Conclusions

Studies included in this review are heterogeneous in study design, biological samples, and outcome. More coordinated investigations are needed to affirm DNA methylation as a clinically relevant biomarker important for prevention, monitoring, and intervention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-022-01241-7.

Acute Treatment Effects on GFR in Randomized Clinical Trials of Kidney Disease Progression

BACKGROUND

Acute changes in GFR can occur after initiation of interventions targeting progression of CKD. These acute changes complicate the interpretation of long-term treatment effects.

METHODS

To assess the magnitude and consistency of acute effects in randomized clinical trials and explore factors that might affect them, we performed a meta-analysis of 53 randomized clinical trials for CKD progression, enrolling 56,413 participants with at least one estimated GFR measurement by 6 months after randomization. We defined acute treatment effects as the mean difference in GFR slope from baseline to 3 months between randomized groups. We performed univariable and multivariable metaregression to assess the effect of intervention type, disease state, baseline GFR, and albuminuria on the magnitude of acute effects.

RESULTS

The mean acute effect across all studies was -0.21 ml/min per 1.73 m2 (95% confidence interval, -0.63 to 0.22) over 3 months, with substantial heterogeneity across interventions (95% coverage interval across studies, -2.50 to +2.08 ml/min per 1.73 m2). We observed negative average acute effects in renin angiotensin system blockade, BP lowering, and sodium-glucose cotransporter 2 inhibitor trials, and positive acute effects in trials of immunosuppressive agents. Larger negative acute effects were observed in trials with a higher mean baseline GFR.

CONCLUSION

The magnitude and consistency of acute GFR effects vary across different interventions, and are larger at higher baseline GFR. Understanding the nature and magnitude of acute effects can help inform the optimal design of randomized clinical trials evaluating disease progression in CKD.

Potential Role and Limitations of Estimated Glomerular Filtration Rate Slope Assessment in Cardiovascular Trials: A Review

Importance

Cardiovascular trials have traditionally been underpowered to assess advanced chronic kidney disease (CKD) outcomes, and when included as a secondary end point, trials have used progression of CKD as incidence of some variation of a composite of end-stage kidney disease (ESKD) outcomes. Such outcomes are infrequent or occur late in cardiovascular outcome trials, which highlights the need for alternate markers for assessing the impact of interventions on kidney function at an earlier stage of the disease and, from the prevention perspective, more relevant stage of the disease.

Observations

Estimated glomerular filtration rate (eGFR) slope has demonstrated strong association with subsequent progression to ESKD. With adequate sample size, treatment effects in the range of 0.5 to 1.00 mL/min/1.73 m2/y had 96% probability of predicting CKD progression, defined as doubling of serum creatinine, eGFR less than 15 mL/min/1.73 m2, or ESKD. eGFR slope can be used in patients with higher baseline values and may provide CKD progression insights when few hard kidney events are observed, especially in trials with limited follow-up. However, among trials that have determined eGFR slope, significant variations exist regarding inclusion of baseline values, calculation of eGFR values, and the follow-up period, which make it difficult to compare and gauge the incremental benefit of the interventions. There are multiple challenges in computing eGFR slope in cardiovascular trials, such as accounting for initial eGFR dip, nonlinearity, and heteroscedasticity.

Conclusions and Relevance

eGFR slope may serve as a valuable marker to determine progression of CKD in cardiovascular trials. Further work is required to standardize data collection, follow-up duration, time points for kidney function assessment, and analytic methods to compute eGFR slope in cardiovascular trials.

Treatments for Chronic Kidney Disease: A Systematic Literature Review of Randomized Controlled Trials

Delaying disease progression and reducing the risk of mortality are key goals in the treatment of chronic kidney disease (CKD). New drug classes to augment renin-angiotensin-aldosterone system (RAAS) inhibitors as the standard of care have scarcely met their primary endpoints until recently. This systematic literature review explored treatments evaluated in patients with CKD since 1990 to understand what contemporary data add to the treatment landscape. Eighty-nine clinical trials were identified that had enrolled patients with estimated glomerular filtration rate 13.9-102.8 mL/min/1.73 m2 and urinary albumin-to-creatinine ratio (UACR) 29.9-2911.0 mg/g, with (75.5%) and without (20.6%) type 2 diabetes (T2D). Clinically objective outcomes of kidney failure and all-cause mortality (ACM) were reported in 32 and 64 trials, respectively. Significant reductions (P < 0.05) in the risk of kidney failure were observed in seven trials: five small trials published before 2008 had evaluated the RAAS inhibitors losartan, benazepril, or ramipril in patients with (n = 751) or without (n = 84-436) T2D; two larger trials (n = 2152-2202) published onwards of 2019 had evaluated the sodium-glucose co-transporter 2 (SGLT2) inhibitors canagliflozin (in patients with T2D and UACR > 300-5000 mg/g) and dapagliflozin (in patients with or without T2D and UACR 200-5000 mg/g) added to a background of RAAS inhibition. Significant reductions in ACM were observed with dapagliflozin in the DAPA-CKD trial. Contemporary data therefore suggest that augmenting RAAS inhibitors with new drug classes has the potential to improve clinical outcomes in a broad range of patients with CKD.

Randomized clinical study to evaluate the effect of personalized therapy on patients with immunoglobulin a nephropathy

Background

Randomized controlled trials (RCTs) have been conducted, stratifying idiopathic immunoglobulin A nephropathy (IgAN) patients based on the laboratory findings [serum creatinine, estimated glomerular filtration rate (eGFR) and daily proteinuria]. In contrast, data from kidney biopsy have been used only for clinical diagnosis. Therefore, IgAN patients with active or chronic renal lesions have been receiving the same therapy in experimental and control arms of randomized clinical trials (RCTs).

Methods

Our clinical study of IgAN (CLIgAN) is a multicentre, prospective, controlled and open-label RCT based on patients’ stratification at the time of their kidney biopsy. We will consider, first, the type of renal lesions, followed by serum creatinine values, eGFR and proteinuria. Primary and secondary endpoints will be monitored. Then, we will determine whether personalized therapy can slow the decline of renal function and delay end-stage kidney disease.

Results

We will enrol 132 IgAN patients with active renal lesions (66 patients per arm) in the first RCT (ACIgAN). They will receive corticosteroids combined with renin–angiotensin system blockers (RASBs) or only RASBs. A total of 294 IgAN patients with chronic or moderate renal lesions at high or very high risk of chronic kidney disease (147 patients per arm) will be enrolled in the second RCT (CHRONIgAN), in which they will receive dapagliflozin, a sodium–glucose cotransporter 2 inhibitor, combined with RASBs, or RASBs alone.

Conclusion

Using this approach, we hypothesize that patients could receive personalized therapy based on renal lesions to ensure that the right drug gets to the right patient at the right time.

Effect of dapagliflozin on the rate of decline in kidney function in patients with chronic kidney disease with and without type 2 diabetes: a prespecified analysis from the DAPA-CKD trial

BACKGROUND

Dapagliflozin reduced the risk of kidney failure in patients with chronic kidney disease with and without type 2 diabetes in the DAPA-CKD trial. In this pre-specified analysis, we assessed the effect of dapagliflozin on the rate of change in estimated glomerular filtration rate (eGFR)-ie, the eGFR slope.

METHODS

DAPA-CKD was a randomised controlled trial that enrolled participants aged 18 years or older, with or without type 2 diabetes, with a urinary albumin-to-creatinine ratio (UACR) of 200-5000 mg/g, and an eGFR of 25-75 mL/min per 1·73m². Participants were randomly assigned (1:1) to oral dapagliflozin 10 mg once daily or placebo, added to standard care. In this pre-specified analysis, we analysed eGFR slope using mixed-effect models with different slopes from baseline to week 2 (acute eGFR decline), week 2 to end of treatment (chronic eGFR slope), and baseline to end of treatment (total eGFR slope). DAPA-CKD is registered with ClinicalTrials.gov, NCT03036150, and is now complete.

FINDINGS

Between Feb 2, 2017, and April 3, 2020, 4304 participants were recruited, of whom 2152 (50%) were assigned to dapagliflozin and 2152 (50%) were assigned to placebo. At baseline, the mean age was 62 years (SD 12), 1425 (33·1%) participants were women, 2906 (67·5%) participants had type 2 diabetes. The median on-treatment follow-up was 2·3 years (IQR 1·8-2·6). From baseline to the end of treatment, dapagliflozin compared with placebo slowed eGFR decline by 0·95 mL/min per 1·73 m² per year (95% CI 0·63 to 1·27) in the overall cohort. Between baseline and week 2, dapagliflozin compared with placebo resulted in an acute eGFR decline of 2·61 mL/min per 1·73 m² (2·16 to 3·06) in patients with type 2 diabetes and 2·01 mL/min per 1·73 m² (1·36 to 2·66) in those without type 2 diabetes. Between week 2 and end of treatment, dapagliflozin compared with placebo reduced the mean rate of eGFR decline by a greater amount in patients with type 2 diabetes (mean difference in chronic eGFR slope 2·26 mL/min per 1·73 m² per year [1·88 to 2·64]) than in those without type 2 diabetes (1·29 mL/min per 1·73 m² per year [0·73 to 1·85]; p_interaction=0·0049). Between baseline and end of treatment, the effect of dapagliflozin compared with placebo on the decline of total eGFR slope in patients with type 2 diabetes was 1·18 mL/min per 1·73 m² per year (0·79 to 1·56) and without type 2 diabetes was 0·46 mL/min per 1·73 m² per year (-0·10 to 1·03; p_interaction=0·040). The total eGFR slope was steeper in patients with higher baseline HbA_1c and UACR; the effect of dapagliflozin on eGFR slope was also more pronounced in patients with higher baseline HbA_1c and UACR.

INTERPRETATION

Dapagliflozin significantly slowed long-term eGFR decline in patients with chronic kidney disease compared with placebo. The mean difference in eGFR slope between patients treated with dapagliflozin versus placebo was greater in patients with type 2 diabetes, higher HbA_1c, and higher UACR.

FUNDING

AstraZeneca.

Ertugliflozin and Slope of Chronic eGFR: Prespecified Analyses from the Randomized VERTIS CV Trial

BACKGROUND AND OBJECTIVES

A reduction in the rate of eGFR decline, with preservation of ≥0.75 ml/min per 1.73 m² per year, has been proposed as a surrogate for kidney disease progression. We report results from prespecified analyses assessing effects of ertugliflozin versus placebo on eGFR slope from the eValuation of ERTugliflozin effIcacy and Safety CardioVascular outcomes (VERTIS CV) trial (NCT01986881).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with type 2 diabetes mellitus and established atherosclerotic cardiovascular disease were randomized to placebo, ertugliflozin 5 mg, and ertugliflozin 15 mg (1:1:1). The analyses compared the effect of ertugliflozin (pooled doses, n=5499) versus placebo (n=2747) on eGFR slope per week and per year by random coefficient models. Study periods (weeks 0-6 and weeks 6-52) and total and chronic slopes (week 0 or week 6 to weeks 104, 156, 208, and 260) were modeled separately and by baseline kidney status.

RESULTS

In the overall population, for weeks 0-6, the least squares mean eGFR slopes (ml/min per 1.73 m² per week [95% confidence interval (95% CI)]) were -0.07 (-0.16 to 0.03) and -0.54 (-0.61 to -0.48) for the placebo and ertugliflozin groups, respectively; the difference was -0.47 (-0.59 to -0.36). During weeks 6-52, least squares mean eGFR slopes (ml/min per 1.73 m² per year [95% CI]) were -0.12 (-0.70 to 0.46) and 1.62 (1.21 to 2.02) for the placebo and ertugliflozin groups, respectively; the difference was 1.74 (1.03 to 2.45). For weeks 6-156, least squares mean eGFR slopes (ml/min per 1.73 m² per year [95% CI]) were -1.51 (-1.70 to -1.32) and -0.32 (-0.45 to -0.19) for the placebo and ertugliflozin groups, respectively; the difference was 1.19 (0.95 to 1.42). During weeks 0-156, the placebo-adjusted difference in least squares mean slope was 1.06 (0.85 to 1.27). These findings were consistent by baseline kidney status.

CONCLUSIONS

Ertugliflozin has a favorable placebo-adjusted eGFR slope >0.75 ml/min per 1.73 m² per year, documenting the kidney function preservation underlying the clinical benefits of ertugliflozin on kidney disease progression in patients with type 2 diabetes mellitus and atherosclerotic cardiovascular disease.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

US National Library of Medicine, ClinicalTrials.gov NCT01986881. Date of trial registration: November 13, 2013.